This invention concerns an electronic device that has multiple boards including a circuit board and a cabinet inside which these multiple boards are accommodated, and in particular, it concerns an assembly of boards that are stacked in a simplified and secure manner within such cabinet.
Heretofore, entertainment devices, personal computers, and other electronic devices that employ an optical disk, such as game machines, CD and DVD players and the like, have been constituted to have a disk device that includes an optical pickup unit, a circuit board on which a CPU and image processing unit are mounted, and a cabinet made up of an upper case and lower case that houses such components. And if for example it is an entertainment device, image information and sound information recorded on an optical disk can be played by detecting it with the optical pickup unit, computation-processing it with the CPU and image processing unit, and outputting video and audio control signals to a display device, etc.
With such an electronic device, the playback of image information and sound information is greatly affected by the processing capacity of the CPU and image processing unit, so it is required that the processing capacity of the CPU and image processing unit be speeded up. Here, when the processing capacity of the CPU and image processing unit is speeded up, the electromagnetic waves emitted from their circuit elements become stronger, and normally measures against EMI are implemented in such electronic devices.
Specifically, if the cabinet is made of ABS resin, etc., anti-EMI measures are accomplished by covering the circuit board, that includes the CPU and image processing unit, with metal shielding plates and ensuring electrical continuity between these shielding plates and the grounding pattern formed on the circuit board, which means that the circuit board is housed inside the cabinet and sandwiched in between two metal shielding plates.
Heretofore, such an electronic device has been assembled by (1) attaching a shielding plate to the base of the upper case of the cabinet, (2) attaching the circuit board onto the shielding plate and fixing the circuit board and shielding plate in place with screws or other means to ensure anchoring and electrical continuity, then (3) attaching another shielding plate onto the circuit board and fixing the shielding plate on the circuit board with screws or other means, (4) putting the upper plate over it, then (5) turning over the electronic device, inserting anchoring screws or other anchoring members into holes formed on the lower surface of the lower case, and joining and anchoring it to the upper case.
But the problem with such a conventional assembly method is that the circuit board and shielding plates must each be screwed in place, which can make the assembly operation more complex. Not only does increasing the number of screw-on locations make the assembly operation more complex, it is also undesirable for making the electronic device smaller. And because the top surface of the cabinet of the electronic device is important for aesthetic design considerations, it is undesirable to allow anchoring screws, etc. to appear on the top surface of the cabinet, and the anchoring screws must be inserted from the lower surface of the lower case, which creates the problem that the operation of flipping over the electronic device during the assembly operation is unavoidable.
It is an object of the present invention, therefore, to provide an electronic device that makes it possible to simplify the assembly operation by reducing the number of screw-on locations and allows it to be made smaller by reducing the number of parts.
It is a further object of the present invention to provide an electronic device having multiple boards that are secured in a simplified manner within such device.
It is a further object of the present invention to provide an electronic device having multiple boards that are anchored to said device and are prevented from moving within said device.
Still other objects and advantages of the invention will become clear upon review of the following detailed description in conjunction with the appended drawings.
An electronic device is provided with a cabinet in which is housed multiple boards including a circuit board. The cabinet is formed by combining two cabinet members, one of which is provided with a recessed part and the other of which is provided with hold-down members. Multiple boards are housed and anchored within said cabinet member by the assembly of said cabinet members.
The use of hold-down members and the manner in which the boards are anchored reduces the number of screw-on locations, which is advantageous for making the electronic device smaller.
In addition, one of he multiple boards consists of a circuit board and two shielding plates cover the front and back surfaces of this circuit board, and the cabinet is made of a synthetic resin such as ABS resin or the like. The two shielding plates cover the front and back surfaces of the circuit board as an anti-EMI measure for the circuit board.
In addition, if a grounding pattern is formed on the board surface of said circuit board, it is desirable that the aforesaid holding-down members be constituted so that they are set in accordance with the shape of this grounding pattern, and when pressure is applied by the joining of the cabinet members, electrical continuity of the grounding pattern with the shielding plates is ensured. Thus, the need to ensure electrical continuity by holding the circuit board and shielding plates in place with screws, etc. is eliminated, which simplifies the assembly operation without detracting from the function of the shielding plates. In addition, forming the grounding pattern on the rim of the circuit board can ensure electrical continuity, securely regulate the movement of the circuit board and shielding plates within the cabinet before they are anchored in place by the anchoring members, and make handling easy during the assembly operation.